Maybe I'm misreading the original post. But if she's already had a dose of Evinity, to change to Tymlos seems to conflict with the posts noting that of one can't follow Evenity with Tymlos.

It would be worth getting a second medical opinion about this from an endocrinologist. And maybe, IF staying on Evenity is a good idea, a different doctor would be willing to work with your insurer to get it covered. There are cases when a patient having adverse effects from a drug the insurer does not cover, cam also be denied coverage to treat or deal with those side effects or any complications. That happened to a friend of mine who ended up in litigation over it. Insurers have a far higher responsibility for drugs they cover and any unintended consequences.